:root {
    --bg: #f5f6f8;
    --surface: #ffffff;
    --text: #111827;
    --muted: #6b7280;
    --accent: #2563eb;
    --accent-soft: rgba(37, 99, 235, 0.1);
    --accent-text: #ffffff;
    --border: #e5e7eb;
    --card: #f9fafb;
    --danger: #dc2626;
    --success: #16a34a;
    --shadow: 0 1px 2px rgba(16, 24, 40, 0.06), 0 1px 3px rgba(16, 24, 40, 0.08);
}

:root[data-theme="dark"] {
    --bg: #0b0c10;
    --surface: #17181d;
    --text: #f2f3f5;
    --muted: #9aa0ac;
    --accent: #3b82f6;
    --accent-soft: rgba(59, 130, 246, 0.18);
    --accent-text: #ffffff;
    --border: #2b2d33;
    --card: #1c1e24;
    --danger: #f87171;
    --success: #4ade80;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 4px 12px rgba(0, 0, 0, 0.35);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 0 16px 32px;
    transition: background-color 0.2s ease, color 0.2s ease;
}

/* ---------- top navbar ---------- */

.topbar {
    width: 100%;
    max-width: 760px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 14px 4px;
    margin-bottom: 32px;
    position: sticky;
    top: 0;
    background: color-mix(in srgb, var(--bg) 85%, transparent);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    z-index: 10;
}

.brand {
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: var(--text);
    font-weight: 700;
    font-size: 16px;
}

.brand-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 9px;
    background: linear-gradient(145deg, var(--accent), #7c3aed);
    color: #fff;
    box-shadow: var(--shadow);
}

.nav {
    display: flex;
    gap: 6px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 4px;
    box-shadow: var(--shadow);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 6px;
    color: var(--muted);
    text-decoration: none;
    font-size: 13.5px;
    font-weight: 600;
    padding: 7px 14px;
    border-radius: 999px;
    transition: background-color 0.15s ease, color 0.15s ease;
    white-space: nowrap;
}

.nav-link:hover {
    color: var(--text);
    background: var(--card);
}

.nav-link.active {
    color: var(--accent-text);
    background: var(--accent);
}

.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: 999px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
    cursor: pointer;
    box-shadow: var(--shadow);
    flex-shrink: 0;
}

.theme-toggle:hover {
    background: var(--card);
}

.theme-toggle .icon-moon { display: none; }
:root[data-theme="dark"] .theme-toggle .icon-sun { display: none; }
:root[data-theme="dark"] .theme-toggle .icon-moon { display: block; }

/* ---------- main content ---------- */

main {
    width: 100%;
    max-width: 480px;
    text-align: center;
}

.clock {
    font-size: 40px;
    font-weight: 700;
    letter-spacing: 1px;
    margin: 4px 0 24px;
    font-variant-numeric: tabular-nums;
}

.block {
    margin-bottom: 22px;
}

.label {
    color: var(--muted);
    font-size: 15px;
    margin-bottom: 4px;
}

.value {
    font-size: 20px;
    font-weight: 600;
}

.value.big {
    font-size: 26px;
}

.status-pill {
    display: inline-block;
    padding: 6px 18px;
    border-radius: 999px;
    background: var(--card);
    border: 1px solid var(--border);
    font-size: 20px;
    font-weight: 700;
}

.status-pill.hoc { color: var(--accent); border-color: var(--accent); }
.status-pill.nghi { color: var(--success); border-color: var(--success); }
.status-pill.off { color: var(--muted); }

.countdown {
    font-variant-numeric: tabular-nums;
}

footer {
    margin-top: 36px;
    color: var(--muted);
    font-size: 13px;
}

/* ---------- config page ---------- */

.tabs {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    justify-content: center;
    margin-bottom: 20px;
}

.tab {
    padding: 6px 14px;
    border-radius: 999px;
    border: 1px solid var(--border);
    background: var(--card);
    color: var(--text);
    cursor: pointer;
    font-size: 14px;
}

.tab.active {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--accent-text);
}

.day-table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 12px;
    font-size: 14px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.day-table th, .day-table td {
    border: 1px solid var(--border);
    padding: 8px 6px;
    text-align: center;
    color: var(--text);
}

.day-table th {
    background: var(--card);
    font-weight: 600;
}

.day-table input, .day-table select {
    width: 100%;
    border: none;
    background: transparent;
    color: var(--text);
    text-align: center;
    font-size: 14px;
    font-family: inherit;
    padding: 4px 2px;
    border-radius: 6px;
    color-scheme: light dark;
}

.day-table input:focus, .day-table select:focus {
    outline: 2px solid var(--accent);
    outline-offset: -2px;
    background: var(--card);
}

.row-actions button {
    border: none;
    background: none;
    color: var(--danger);
    cursor: pointer;
    font-size: 16px;
}

.btn {
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
    padding: 8px 16px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    margin: 4px;
    box-shadow: var(--shadow);
}

.btn:hover {
    background: var(--card);
}

.btn.primary {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--accent-text);
}

.btn.danger {
    color: var(--danger);
    border-color: var(--danger);
    background: var(--surface);
}

.actions {
    margin-top: 16px;
    text-align: center;
}

.io {
    margin-top: 24px;
    text-align: left;
}

.io textarea {
    width: 100%;
    height: 140px;
    font-family: ui-monospace, monospace;
    font-size: 12px;
    padding: 8px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--surface);
    color: var(--text);
    color-scheme: light dark;
}

.msg {
    margin-top: 10px;
    font-size: 13px;
    color: var(--muted);
    min-height: 18px;
}